EP0092859A2 - Ionendetektor - Google Patents

Ionendetektor Download PDF

Info

Publication number
EP0092859A2
EP0092859A2 EP83200472A EP83200472A EP0092859A2 EP 0092859 A2 EP0092859 A2 EP 0092859A2 EP 83200472 A EP83200472 A EP 83200472A EP 83200472 A EP83200472 A EP 83200472A EP 0092859 A2 EP0092859 A2 EP 0092859A2
Authority
EP
European Patent Office
Prior art keywords
electrode
chamber
guard ring
electronic circuit
chambers
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP83200472A
Other languages
English (en)
French (fr)
Other versions
EP0092859A3 (de
Inventor
Jacques Depoitier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Institut National des Radioelements IRE
Original Assignee
Institut National des Radioelements IRE
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from BE0/207934A external-priority patent/BE892985A/fr
Application filed by Institut National des Radioelements IRE filed Critical Institut National des Radioelements IRE
Publication of EP0092859A2 publication Critical patent/EP0092859A2/de
Publication of EP0092859A3 publication Critical patent/EP0092859A3/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/11—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using an ionisation chamber for detecting smoke or gas
    • G08B17/113—Constructional details

Definitions

  • the present invention relates to an ion detector with two ionization chambers called measurement or analysis chamber which is partially perforated and reference chamber which is sealed, electrically connected in series and arranged on either side of a circuit mounted, on a support which is a good conductor of electricity and to which the electrodes of the ionization chambers, a voltage source and a warning device are connected, the elements constituting this circuit being embedded in a mass of resin with very high resistivity, each of the abovementioned chambers comprising at least one wall which is a good conductor of electricity constituting a first electrode, a second electrode and a radioactive source housed in the chamber, the second electrodes of the two chambers being electrically connected through the mass of the above resin.
  • said known detectors can have the disadvantage of having their sensitivity which gradually decreases until they become inoperative because, when they are placed under the influence of corrosive atmospheres, the surface resistance of the mass of resin exposed in the measurement chamber decreases and the impedance between the aforementioned support and the electrical connection of the second electrodes of the measurement chamber and the reference chamber is no longer sufficient so that a reduction in ion current due to the combustion gases is analyzed.
  • the object of the invention is to remedy this drawback and to provide a detector which goes into permanent alarm when it is no longer able to analyze correctly a decrease in the ion current, which is exchanged between the two electrodes of the measurement chamber, due to the presence of combustion gases, which constitutes an essential safety element of a detection circuit.
  • the electronic circuit comprises a guard ring having a loop arranged, outside the resin mass, in the measurement chamber, this guard ring being brought to the potential opposite to that of the aforementioned support of the electronic circuit.
  • the loop of the aforementioned guard ring is disposed between the second electrode of the measurement chamber and the surface of the resin mass, embedding the components of the electronic circuit, facing this second electrode.
  • the second electrode of the measurement chamber has a rim directed towards the above-mentioned surface of the resin mass in order to delimit an enclosure, comprised between this surface, the face of the second electrode and the internal face of the rim turned towards said surface, ( h ns which is the above-mentioned loop of the guard ring so that the disturbing electric field of the latter is shielded by the second electrode of the measurement chamber, this enclosure communicating with the measurement chamber through a peripheral space formed between the free edge of the rim and the aforementioned surface of the mass of resin.
  • the drawing is a view in elevation and in section of the ion detector according to the invention.
  • the ion detector according to the invention and shown in the drawing is a detector of the type described in Belgian patent N ° 874,157 and includes two ionization chambers, a chamber 1 called measurement or analysis, and a chamber 2, called reference, arranged in a housing 3 on either side of a plate 4 mounted on a support 5 good conductor of electricity and supporting an electronic circuit 6 to which the electrodes of the chambers 1 and 2 as well as the voltage source and a warning device are connected, the elements constituting this circuit being embedded in a mass of resin 7 with very high resistivity.
  • the measurement chamber 1 comprises a wall 8 which is a good conductor of electricity which constitutes a first electrode and which has openings 9 to allow the entry of combustion gases into said chamber, a second electrode 10 and a radioactive source a 11, for example a source of americium 241, associated with the electrode 10.
  • the reference chamber 2 comprises a wall 12 good conductor of electricity constituting the first electrode, a second electrode 13 and a source a 14, the chamber 2 being protected by a sealed cover 15 and the electrodes 10 and 13 of the chambers and 2 being electrically connected, at 16, through the mass of resin 7.
  • the mass of resin 7 which shelters the elements constituting the above-mentioned circuit from aggressive atmospheres can, under the influence of corrosive atmospheres, have its surface resistance which decreases and then the impedance between the support 5 and the electrical connection 16 of the electrodes 10 and 13 of the chambers 1 and 2 becomes insufficient for a reduction in the ion current due to the combustion gases to be analyzed. As the surface resistance decreases, the detector has a decreasing sensitivity and finally becomes inoperative, without being noticed.
  • the detector according to the invention is provided with a guard ring 17 having a loop 18 disposed in the chamber 1, outside the resin mass 7, intended to trigger the warning device when the detector becomes too insensitive to effectively fulfill its role.
  • the guard ring is brought to the potential opposite to that of the support 5 and is connected to the wall 12 of the reference chamber 2 via a resistor 19, this wall also being at the reverse potential of said support 5.
  • This guard ring which advantageously has its loop 18 disposed between the electrode 10 of the chamber 1 and the surface 20 of the resin mass 7, will cause, in the event of a decrease in the impe above-mentioned surface dance, the same effect as combustion gases entering chamber 1 so that the detector will become more sensitive and finally go into permanent alarm.
  • the particular profile of the electrode 10 of the measurement chamber which has a flange 21 directed towards the surface 20 makes it possible to delimit an enclosure 22 comprised between the latter, the face of the electrode 10 and the internal face of the flange 21 turned towards said surface 20, this enclosure 22, in which the loop 18 of the guard ring is disposed, being open at the periphery of the rim 21 so as to communicate with the chamber 1.
  • This particular arrangement of the loop 18 of the guard ring and electrodes 10 and 8 of chamber 1 allows the presence of the guard ring in the detector because the electric field created by this ring is shielded by electrode 10 and cannot therefore disturb the main field prevailing between the electrodes 8 and 10.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Fire-Detection Mechanisms (AREA)
EP83200472A 1982-04-27 1983-04-05 Ionendetektor Withdrawn EP0092859A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BE207934 1982-04-27
BE0/207934A BE892985A (fr) 1982-04-27 1982-04-27 Detecteur ionique

Publications (2)

Publication Number Publication Date
EP0092859A2 true EP0092859A2 (de) 1983-11-02
EP0092859A3 EP0092859A3 (de) 1985-11-21

Family

ID=3843525

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83200472A Withdrawn EP0092859A3 (de) 1982-04-27 1983-04-05 Ionendetektor

Country Status (1)

Country Link
EP (1) EP0092859A3 (de)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5552558Y2 (de) * 1975-02-10 1980-12-05
GB2014782B (en) * 1978-01-05 1982-06-23 Sound Diffusion Ltd Ionization smoke detectors
BE892985A (fr) * 1982-04-27 1982-08-16 Inst Nat Radio Elements Detecteur ionique

Also Published As

Publication number Publication date
EP0092859A3 (de) 1985-11-21

Similar Documents

Publication Publication Date Title
ES3013927T3 (en) Water meter systems
US4350660A (en) Ammonia gas sensors
FR2767201A1 (fr) Dosimetre personnel de rayonnement
US4992658A (en) Electret ion chamber for radon monitoring
EP0025725A2 (de) Elektronische Anlage für die Verwendung einer Quelle mit sehr schwacher Spannung und ihre Anwendung in einem Feuerdetektor-Sender
FR2523309A1 (fr) Nouveau detecteur de fumees capacitif a modules interchangeables
US4044262A (en) Ionization smoke sensor
US3942167A (en) Immersion responsive sensor
EP0490783A2 (de) Neutrondetektoranordnung mit erweitertem dynamischem Messbereich für Kontrolle und Steuerung von Kernreaktoren
US3909815A (en) Detector for fumes and combustion gases
WO2004112167A3 (en) Fuel cell device condition detection
FR2473201A1 (fr) Detecteur de fumees capacitif a faible source d'ionisation
EP0092859A2 (de) Ionendetektor
US4068221A (en) Immersion responsive sensor
FR2528487A1 (fr) Dispositif pour la surveillance des locaux blindes, surtout des chambres fortes et coffres-forts
BE892985A (fr) Detecteur ionique
US4924098A (en) Nuclear radiation level detector
FR2693556A1 (fr) Procédé et dispositif de détection d'une perturbation électrique ionique dans une zone déterminée d'un milieu et leur utilisation.
FR2600777A1 (fr) Dispositif de detection d'une impulsion electromagnetique, due notamment a une explosion nucleaire
CA1263767A (fr) Detecteur electrique de particules pour la detection d'incendie
US3781838A (en) Products of combustion detector
FR2528980A1 (fr) Detecteur de niveau d'ionisation d'un milieu gazeux controle par arc electrique
SE0500490L (sv) Detektor för joniserande strålning
EP0173606B1 (de) Thermosiegelüberwachungsvorrichtung für einen thermogenischen Stoff enthaltenden Behälter
BE854653A (fr) Detecteur de faux rond pour turbines a gaz

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE FR NL

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Designated state(s): DE FR NL

17P Request for examination filed

Effective date: 19851231

17Q First examination report despatched

Effective date: 19870529

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19871009

RIN1 Information on inventor provided before grant (corrected)

Inventor name: DEPOITIER, JACQUES